Rotary damper

ABSTRACT

A rotary damper is provided. The rotary damper includes a first housing plate having a substantially flat substrate with a first plurality of windows; a rotary disc having a substantially flat substrate with a second plurality of windows, wherein the rotary disc is in rotatable communication with the first housing plate; and a motor that drives rotation of the rotary disc relative to the first housing plate such that the rotary disc rotates from a first configuration in which the second plurality of windows overlaps with the first plurality of windows of the first housing plate to at least a second configuration in which the second plurality of windows on the rotary disc and the first plurality of windows on the first housing plate do not overlap. Also provided is a refrigeration/freezer unit utilizing the rotary damper to control airflow between a freezer compartment and a refrigeration compartment.

FIELD OF THE INVENTION

This invention generally relates to an airflow control device and more particularly to an airflow control device for refrigerated air.

BACKGROUND OF THE INVENTION

Refrigerators frequently are sold as combination refrigerator/freezer units that are cooled using a single cooling system. For instance, one common method for cooling a refrigerator/freezer unit is to circulate the air in the freezer compartment over evaporator coils. The cooled air is then used to keep food items in the freezer frozen, and in order to keep the food items in the refrigerator chilled, a portion of the cooled air in the freezer compartment is provided to the refrigeration compartment.

Because of the temperature difference between the freezer and refrigerator compartments of a refrigerator/freezer unit, the cooled air from the evaporator is used in the freezer. Thus, in many commonly available refrigerator/freezer units, air that has been cooled at the evaporator coils flows first to the freezer, and then a portion of the air from the freezer flows into the refrigerator compartment. The pathway between the refrigerator and freezer compartments is controlled by a damper. By opening and closing the damper, more or less cold air can flow from the freezer compartment to the refrigerator compartment.

Because the air circulated in refrigerator/freezer unit is taken from the ambient air where the refrigerator/freezer unit is located and because moisture evaporates from unsealed food in the refrigerator compartment, the air in a refrigerator is relatively humid. Additionally, users open the refrigerator door to access the food items contained therein, which causes a large influx of ambient humid air. This moisture in the air frequently causes ice to build up in the damper, which, in turn, can cause a partial or total blockage of airflow through the damper. A partial blockage will prevent the air in the refrigerator compartment from reaching the desired level of coolness. In response, the thermostat will force the coolant compressor to work harder, which can cause it to fail prematurely, leading to an expensive repair or replacement. A total blockage prevents air in the refrigerator compartment from being cooled, which not only causes stress on the compressor and other cooling components but also may cause the food items to spoil.

Conventional door- and gate-style dampers frequently suffer from such ice buildup. As a consequence, many of these dampers have a built-in heater to melt the ice buildup, which increases the energy usage of the heater. Moreover, these dampers are large, which diminishes the amount of space available in the refrigerator for storing food items. Additionally, these dampers can be noisy during operation.

BRIEF SUMMARY OF THE INVENTION

Disclosed herein are embodiments of a rotary damper that address many of the deficiencies related to conventional dampers. The rotary damper has a high torque output, which reduces the risk that the damper will fail as a result of ice buildup. Further, the design is much slimmer than conventional designs, which increases the storage capacity of the refrigerator/freezer unit. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

In one aspect, embodiments of a rotary damper are provided. The rotary damper includes a first housing plate having a substantially flat substrate with a first plurality of windows. The rotary damper also includes a rotary disc having a substantially flat substrate with a second plurality of windows. The rotary disc is in rotatable communication with the first housing plate. The rotary damper also includes a motor that drives rotation of the rotary disc relative to the first housing plate such that the rotary disc rotates from a first configuration in which the second plurality of windows overlaps with the first plurality of windows of the first housing plate to at least a second configuration in which the second plurality of windows on the rotary disc and the first plurality of windows on the first housing plate do not overlap.

In an embodiment, the rotary damper further includes a gear wheel adapted to translate rotational forces from the motor to the rotary disc.

In an embodiment of the rotary damper, the gear wheel translates rotational forces from the motor such that the rotary disc rotates at a lower speed than the motor and at a higher torque.

In an embodiment, the rotary damper further includes a second housing plate having a substantially flat substrate with a third plurality of windows. In such embodiment, the rotary disc is encompassed by the first housing plate and the second housing plate, and the third plurality of windows of the second housing plate substantially overlap with the first plurality of windows of the first housing plate.

In an embodiment of the rotary damper, the motor is a permanent magnet synchronous motor.

In an embodiment of the rotary damper, the motor is controlled by at least one microswitch and by a thermostat.

In certain embodiments, the rotary damper further includes at least one circumferential ridge extending from a surface of the substantially flat substrate of the rotary disc. In such embodiments, the at least one circumferential ridge includes a plurality of breaks around a circumference of the circumferential ridge, and at least one microswitch has a lever arm that contacts a circumferential ridge.

In an embodiment of the rotary damper, the microswitch is a double pole, double throw switch.

In an embodiment, the rotary damper includes two microswitches and two circumferential ridges that extend from opposite surfaces of the substantially flat substrate of the rotary disc. In such embodiments, the two microswitches each have a lever arm, and the lever arms of the two microswitches contact different circumferential ridges. Both circumferential ridges include a plurality of breaks around their circumferences, and the plurality of breaks of one circumferential ridge are located at different positions from the plurality of breaks of the other circumferential ridge.

In an embodiment of the rotary damper, the two microswitches are single pole, single throw switches.

In another aspect, embodiments a refrigerator/freezer unit are provided. The refrigerator/freezer unit includes a refrigeration compartment and a freezer compartment. An air passage provides fluid communication between the refrigeration compartment and the freezer compartment. The refrigerator/freezer unit also includes a rotary damper that is configured to regulate the amount of air flowing through the air passage. The rotary damper includes a first housing plate having a substantially flat substrate with a first plurality of windows. The rotary damper also includes a rotary disc having a substantially flat substrate with a second plurality of windows. The rotary disc is in rotatable communication with the first housing plate. The rotary damper also includes a motor that drives rotation of the rotary disc relative to the first housing plate such that the rotary disc rotates from a first configuration in which the second plurality of windows overlaps with the first plurality of windows of the first housing plate to at least a second configuration in which the second plurality of windows on the rotary disc and the first plurality of windows on the first housing plate do not overlap.

In an embodiment of the refrigerator/freezer unit, the freezer compartment is located above the refrigeration compartment, and the rotary damper is located on an upper wall of the refrigeration compartment.

In an embodiment of the refrigerator/freezer unit, the freezer compartment is located below the refrigeration compartment.

In an embodiment of the refrigerator/freezer unit, the freezer compartment is located side-by-side with the refrigeration compartment and wherein the damper is located on a partitioning wall that separates the freezer compartment and the refrigeration compartment.

In an embodiment of the refrigerator/freezer unit, the refrigerator/freezer unit further includes a thermostat. The temperature sensed by the thermostat determines to what extent the second plurality of windows of the rotary disc overlap with first plurality of windows of the first housing plate.

In an embodiment of the refrigerator/freezer unit, at least one microswitch is interposed between the thermostat and the motor. The microswitch has a lever arm that contacts a circumferential ridge that extends from at least one surface of the substantially flat substrate of the rotary disc and that includes a plurality of breaks.

In an embodiment of the refrigerator/freezer unit, the plurality of windows of the rotary disc and the plurality of windows of the first housing plate are wider at their outermost radial extent than they are at their innermost radial extent.

In an embodiment of the refrigerator/freezer unit, the plurality of windows of the rotary disc is four windows and wherein the plurality of windows of the first housing plate is also four windows.

In an embodiment of the refrigerator/freezer unit, the rotary damper further includes a second housing plate defined by substantially flat substrate having a third plurality of windows. In such embodiments, the rotary disc is encompassed by the first housing plate and the second housing plate, and the third plurality of windows of the second housing plate substantially overlap with the first plurality of windows of the first housing plate.

In an embodiment of the refrigerator/freezer unit, the rotary damper further comprises a gear wheel adapted to translate rotational forces from the motor to the rotary disc.

Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

FIG. 1 depicts a refrigerator/freezer unit with a rotary damper according to an exemplary embodiment;

FIG. 2 depicts an isometric view of a rotary damper according to an exemplary embodiment;

FIG. 3 depicts an exploded view of the rotary damper depicted in FIG. 2 according to an exemplary embodiment;

FIG. 4 depicts a view of a rotary damper in a fully open configuration according to an exemplary embodiment;

FIG. 5 depicts a view of a rotary damper in a fully closed configuration according to an exemplary embodiment;

FIG. 6 depicts a view of the internal components that drive the rotary damper according to an exemplary embodiment; and

FIGS. 7A-7B depict control diagrams for the thermostat and switch arrangement of the rotary damper according to exemplary embodiments.

While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of a rotary damper are provided. In one particular application, the rotary damper is designed to regulate the flow of cooled air from a freezer compartment to a refrigeration compartment of a refrigerator/freezer unit. However, as will be recognized by those skilled in the art from the following description, such embodiments are provided by way of example only, not by way of limitation, and that all alternative embodiments are reserved herein.

A refrigerator/freezer unit 10 is provided in FIG. 1. As depicted, the refrigeration compartment 12 is located below the freezer compartment 14; however, in other embodiments, the refrigeration compartment can be located above or on the side of the freezer compartment. A partition, or partitioning wall, 20 divides the freezer compartment 14 from the refrigeration compartment 12 and, in the embodiment depicted in FIG. 1, defines an upper wall 22 for the refrigeration compartment 12. The refrigeration compartment 12 is further defined by sidewalls 24 a, 24 b, bottom wall 26, back wall 28, and refrigerator door 30. The refrigerator door 30 can open or close both the refrigeration compartment 12 and freezer compartment 14, or as depicted in FIG. 1, a separate freezer door 32 can be provided for the freezer compartment 14. The interior of the refrigeration compartment 12 can further contain a plurality of shelves 34, drawers 36, or both for storing food items within the refrigeration compartment 12 and/or freezer compartment 14.

As discussed, a damper provides airflow between the freezer compartment 14 and the refrigeration compartment 12. As depicted in FIG. 1, a rotary damper 40 is located on the upper wall 22 of the refrigeration compartment 12. However, the rotary damper 40 could also be placed on the back wall 28 or one of the sidewalls 24 a, 24 b. In any of these cases, a vent with a fan (not shown) in the freezer compartment 14 and appropriate ducting or an air passage (not shown) from the vent to the rotary damper 40 are provided to create fluid communication of air from the freezer compartment 14 to the refrigeration compartment 12.

FIG. 2 depicts the rotary damper 40 according to an exemplary embodiment. The rotary damper 40 is generally comprised of a substantially circular rotary disc 42 encompassed by a first housing plate 43 and a second housing plate 44. In one embodiment, the second housing plate 44 is not included such that the upper wall 22, sidewalls 24 a, 24 b, or back wall 28 (shown in FIG. 1) opposes the first housing plate 43 to encompass the rotary disc 42. As shown in FIG. 2, the first and/or second housing plates 43, 44 are substantially circular but also include a protruding region 45 onto which a motor 46 is mounted.

The motor 46 is controlled by one or more switches 48 and a thermostat (not shown). In another embodiment, the thermostat is controlled through the use of dials or knobs that a user manually adjusts and which are located in one of the refrigeration compartment 12 or freezer compartment 14. Electrical communication is established between the controller or manual controls and switches 48 via wires from the thermostat. The switches 48 are secured to a mounting plate 52 that extends from the second housing plate 44. Alternatively, the mounting plate 52 can extend from the first housing plate 43 if, for instance, the embodiment does not include the second housing plate 44. The switch or switches 48 include a socket or sockets 50 through which electrical communication is established between the switches 48 and the thermostat. In one embodiment, the switches 48 are microswitches, having a lever arm 49. In such an embodiment, an aperture 51 (shown in FIG. 3) in the first housing plate 43 and/or second housing plate 44 is provided at the location of the lever arm 49 such that the lever arm 49 is allowed to contact the rotary disc 42.

As can be seen from the exploded view of the damper in FIG. 3, the rotary damper 40 further comprises a gear wheel 54. The gear wheel 54 is operably connected to a first small gear 55 that engages a plurality of gear teeth 56 on the outer periphery of the rotary disc 42. Rotational forces from the motor 46 are transferred to the rotary disc 42 via the engagement of the first small gear 55 of the gear wheel 54 and the gear teeth 56. Rotation of the rotary disc 42 occurs about an axis running through a center aperture 58 of the rotary disc 42.

The rotary damper 40 controls the amount of air flowing into the refrigeration compartment 12 by opening to allow cooled air to flow through or closing to shut off the flow of cooled air. Thus, the rotary disc 42 includes a flat substrate 60 containing a plurality of windows 62. The first housing plate 43 also contains a flat substrate 64 defining a plurality of windows 66. The second housing plate 44 similarly contains a flat substrate 68 and a plurality of windows 70. In an embodiment, the windows 66, 70 of the first and second housing plates 43, 44 are the same size and shape and are aligned with each other in an assembled rotary damper. Additionally, in an embodiment, the windows 62 of the rotary disc 42 are the same size and shape as the windows 66, 70 of the first and second housing plate 43, 44. Because the rotary disc 42 rotates within the first and second housing plates 43, 44, the windows 62 of the rotary disc 42 can be brought into an out of alignment with the windows 66, 70 of the first and second housing plates 43, 44. In this way, the rotary disc 42 can partially or fully obstruct the windows 66, 70 or partially or completely open the windows 66, 70.

As shown in FIG. 4, when the windows 62 of the rotary disc 42 are in alignment with the windows 66, 70 of the first and second housing plates 43, 44, a maximum amount of airflow through the rotary damper 40 is provided. As shown in FIG. 5, when the substrate 60 of the rotary disc 42 fully eclipses the windows 66, 70, no air flows through the rotary damper 40. FIG. 2 depicts a configuration in which the rotary disc 42 is partially obstructing air flow through the damper 40, such as when the rotary disc 42 is transitioning between open and closed states.

Returning to FIG. 3, the windows 62, 66, 70 depicted in the figures are substantially wedged-shaped, i.e., the windows 62, 66, 70 are wider at their outermost radial extent 62 a, 66 a, 70 a than they are at their innermost 62 b, 66 b, 70 b radial extent. Nevertheless, the windows 62, 66, 70 can be any of a variety of shapes, such as elongated slits, circles, quadrilaterals, other regular and irregular polygonal shapes, and/or various curved shapes. Also as depicted in the figures, there are four windows 62, 66, 70. However, more or less windows 62, 66, 70 can be provided. For instance, if narrow, elongated slits are used as the window shape, then more of the narrow, elongated slits can be provided to achieve the same airflow capability as using the four wedge-shaped windows depicted in the figures.

FIG. 6 depicts the internal components of the rotary damper 40. As discussed, the rotary disc 42 rotates about an axis running through the central aperture 58. On the underside of the first housing plate 43, a tri-wall mandrel 72 is provided and extends through the central aperture 58 of the rotary disc 42. The tri-wall mandrel 72 centers the rotary disc 42 within the rotary damper 40 while also allowing for rotation of the rotary disc 42. In other embodiments, a single wall mandrel or a solid spindle can also be used to provide rotation about the axis running through the central aperture 58.

As shown in FIG. 6, the motor 46 includes a driveshaft 74 around which a second small gear 76 is provided. The second small gear 76 transmits force from the motor 46 to the gear wheel 54. The gear wheel 54 rotates about a spindle 78 that extends from the underside of the protruding region 45. The first small gear 55, which is operably connected to the gear wheel 54, rotates in conjunction with the gear wheel 54. In one embodiment, the first small gear 55 is integrally molded with the gear wheel 54. The teeth of the first small gear 55 engage the peripheral gear teeth 56 of the rotary disc 42. Through this system of gears, rotational forces produced in the motor 46 are transmitted to the rotary disc 42. Additionally, because the rotary disc 42 acts as a large gear, the increase in gear size from second small gear 76 of the motor 46 to the rotary disc 42 creates an increase in the torque output for the rotary disc 42. Put differently, the increase in gear size from the second small gear 76 to the rotary disc 42 causes a decrease in rotational speed for the rotary 42 but an increase in torque output. Accordingly, the torque of the rotary disc 42 allows the rotary damper 40 to operate despite the potential buildup of ice in the windows 66 of the first housing plates 43 and windows 70 (not shown) of the second housing plate 44 (not shown) by breaking through such potential buildups. In further embodiments, the motor 46 or gear wheel 54 can directly drive the rotary disc 42 either by directly engaging the rotary disc 42 or through a chain and sprocket or belt driven system.

Returning to FIG. 3, the rotary disc 42, in one embodiment, includes a first circumferential ridge 82 that extends upwardly (with reference to the arrangement of components in the figures) towards the first housing plate 43 and a second circumferential ridge 84 that extends downwardly towards the second housing plate 44 from each surface of the rotary disc 42. These circumferential ridges 82, 84 are received into channels 86 formed circumferentially around the substrates 64, 68 of the first and second housing plates 43, 44. The channel 86 formed into the second housing plate 44 is most clearly shown in FIG. 3. While the figures depict two circumferential ridges 82, 84, the rotary disc 42 could also have only a single circumferential ridge on either surface of the rotary disc 42.

FIG. 3 also shows that the first and second circumferential ridges 82, 84 contain a plurality of breaks 88. FIG. 6 provides a closer view of the breaks 88 included in the second circumferential ridge 84. It can be seen that on one side of the break 88 an angled surface 90 is provided.

The microswitch has a normally open switch and a normally closed switch that are selected between using the lever arm 49. The rotary disc 42 will go from a first state in which the lever arm 49 of the microswitch 48 is located within a break 88 through a transition state in which the lever arm 49 travels along the inclined surface 90 to a second state in which the lever arm 49 is fully depressed against the outer periphery of the circumferential ridge 84. Depressing the lever arm 49 will cause the microswitch 48 to transition the path of electrical communication from the normally closed switch to the normally open switch. In conjunction with the thermostat or manual controls, electrical current to the motor 46 is controlled by the microswitch 48, thereby causing rotation of rotary disc 42 until the lever arm 49 reaches another break 88. FIG. 7A provides a control diagram for a rotary damper having a thermostat and single microswitch. In this embodiment, the microswitch is a double pole, double throw switch. As can be seen in FIG. 7A, the thermostat will sense that the temperature in the refrigeration compartment is too high, activating the thermostat. At the same time, the microswitch activates for a time corresponding to transition between breaks in the circumferential ridge, which causes rotation of the rotary damper to the open state for cooling. The microswitch will then deactivate. When the thermostat senses that the desired temperature has been reached, it will deactivate. At that time, the microswitch will re-activate, causing rotation of the damper to a closed state.

Because the rotary disc 42 can include two circumferential ridges 82, 84, two microswitches 48 could be used to drive the motor 46. FIG. 7B shows an embodiment in which two microswitches are utilized. In this embodiment, the microswitches are both single pole, single throw switches. Thus, one switch will activate to cause the rotary disc to transition to the open state and the other switch will activate to cause the rotary disc to transition to the closed state.

Additionally, the breaks 88 in the two circumferential ridges 82, 84 could be provided in multiple and varied locations to increase the control over the rotation of the rotary disc 42 and vary the number of discrete positions in which the rotary disc 42 can exist relative to the first housing plate 43 and second housing plate 44.

In one embodiment, the motor 46 is a permanent magnet synchronous motor (PMSM). Using a PMSM, the rotary damper 40 can provide multiple rotary disc 42 positions corresponding to varying degrees of air flow through the rotary damper 40. Additionally, the PMSM motor produces a high torque output, even at low speeds, which enables the rotary disc 42 to be moved through any ice that may have formed over the windows 66, 70. Further, the PMSM can be operated using one or two microswitches, depending on the number of rotary disc positions desired, without the need for electronics to drive the motor or read the feedback.

The foregoing embodiments of the rotary damper 40 provide several advantages for the regulation of air flow between a refrigeration compartment 12 and a freezer compartment 14. For instance, the design is substantially slimmer than the conventional gate- and door-style dampers, which provides additional room within the refrigeration compartment 14 for the storage of food items. Additionally, the slim design allows for greater flexibility in the placement of the damper within the refrigeration compartment 12. Further, the risk of malfunction as a result of ice buildup is substantially reduced as a result of the increased torque output of the damper, providing consistent and reliable operation of the device. Further still, use of a synchronized motor and mircoswitch eliminates the requirement of electronics to drive the motor and read the feedback from the motor.

All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 

What is claimed is:
 1. A rotary damper, comprising: a first housing plate having a substantially flat substrate with a first plurality of windows; a rotary disc having a substantially flat substrate with a second plurality of windows, wherein the rotary disc is in rotatable communication with the first housing plate; and a motor that drives rotation of the rotary disc relative to the first housing plate such that the rotary disc rotates from a first configuration in which the second plurality of windows overlaps with the first plurality of windows of the first housing plate to at least a second configuration in which the second plurality of windows on the rotary disc and the first plurality of windows on the first housing plate do not overlap.
 2. The rotary damper of claim 1, further comprising a gear wheel adapted to translate rotational forces from the motor to the rotary disc.
 3. The rotary damper of claim 2, wherein the gear wheel translates rotational forces from the motor such that the rotary disc rotates at a lower speed than the motor and at a higher torque.
 4. The rotary damper of claim 1, further comprising a second housing plate having a substantially flat substrate with a third plurality of windows, wherein the rotary disc is encompassed by the first housing plate and the second housing plate and wherein the third plurality of windows of the second housing plate substantially overlap with the first plurality of windows of the first housing plate.
 5. The rotary damper of claim 1, wherein the motor is a permanent magnet synchronous motor.
 6. The rotary damper of claim 1, wherein the motor is controlled by at least one microswitch and by a thermostat.
 7. The rotary damper of claim 5, further comprising at least one circumferential ridge extending from a surface of the substantially flat substrate of the rotary disc, wherein the at least one circumferential ridge includes a plurality of breaks around a circumference of the circumferential ridge and wherein the at least one microswitch has a lever arm that contacts a circumferential ridge.
 8. The rotary damper of claim 6, wherein the microswitch is a double pole, double throw switch.
 9. The rotary damper of claim 6, comprising two microswitches and two circumferential ridges that extend from opposite surfaces of the substantially flat substrate of the rotary disc, wherein the two microswitches each have a lever arm, the lever arms of the two microswitches contacting different circumferential ridges, and wherein both circumferential ridges include a plurality of breaks around their circumferences, the plurality of breaks of one circumferential ridge being located at different positions from the plurality of breaks of the other circumferential ridge.
 10. The rotary damper of claim 8, wherein the two microswitches are single pole, single throw switches.
 11. A refrigerator/freezer unit, comprising: a refrigeration compartment; a freezer compartment, wherein an air passage provides fluid communication between the refrigeration compartment and the freezer compartment; and a rotary damper configured to regulate the amount of air flowing through the air passage, the rotary damper comprising: a first housing plate defined by a substantially flat substrate having a first plurality of windows; a rotary disc defined by a substantially flat substrate having a second plurality of windows, wherein the rotary disc is in rotatable communication with the first housing plate; and a motor that drives rotation of the rotary disc relative to the first housing plate such that the rotary disc rotates from a first configuration in which the second plurality of windows overlap with the first plurality of windows of the first housing plate to at least another configuration in which the second plurality of windows on the rotary disc and the first plurality of windows on the first housing plate do not overlap.
 12. The refrigerator/freezer unit of claim 11, wherein the freezer compartment is located above the refrigeration compartment and wherein the rotary damper is located on an upper wall of the refrigeration compartment.
 13. The refrigerator/freezer unit of claim 11, wherein the freezer compartment is located below the refrigeration compartment.
 14. The refrigerator/freezer unit of claim 11, wherein the freezer compartment is located side-by-side with the refrigeration compartment and wherein the damper is located on a partitioning wall that separates the freezer compartment and the refrigeration compartment.
 15. The refrigerator/freezer unit of claim 11, further comprising a thermostat, wherein a temperature sensed by the thermostat determines to what extent the second plurality of windows of the rotary disc overlap with first plurality of windows of the first housing plate.
 16. The refrigerator/freezer unit of claim 15, wherein at least one microswitch is interposed between the thermostat and the motor and wherein the microswitch has a lever arm that contacts a circumferential ridge that extends from at least one surface of the substantially flat substrate of the rotary disc and that includes a plurality of breaks.
 17. The refrigerator/freezer unit of claim 11, wherein the second plurality of windows of the rotary disc and the first plurality of windows of the first housing plate are wider at their outermost radial extent than they are at their innermost radial extent.
 18. The refrigerator/freezer unit of claim 16, wherein the second plurality of windows of the rotary disc is four windows and wherein the first plurality of windows of the first housing plate is also four windows.
 19. The refrigerator/freezer unit of claim 11, wherein the rotary damper further comprises a second housing plate defined by substantially flat substrate having a third plurality of windows, wherein the rotary disc is encompassed by the first housing plate and the second housing plate and wherein the third plurality of windows of the second housing plate substantially overlap with the first plurality of windows of the first housing plate.
 20. The refrigerator/freezer unit of claim 11, wherein the rotary damper further comprises a gear wheel adapted to translate rotational forces from the motor to the rotary disc. 